Base station, terminal, and communication method

ABSTRACT

At a base station, a control unit selects one combination from multiple combinations of parameters regarding uplink control channel (PUCCH) resources. A transmission unit indicates a terminal of resource settings (Semi-static resource configuration) including the multiple combinations by higher layer signaling, and indicates the terminal of the one combination that has been selected by dynamic signaling (DCI).

TECHNICAL FIELD

The present disclosure relates to a base station, a terminal, and acommunication method.

BACKGROUND ART

As services using mobile broadband have come into widespread use inrecent years, the data traffic in mobile communication has continuouslyseen exponential growth, and expanding data transmission capacity isimperative for the future. Also, dramatic development is anticipated forthe IoT (Internet of Things), where all “things” are connected via theInternet in the future. In order to support diversity in services by theIoT, dramatic sophistication is demanded for various requisites such aslow-delay and communication area (coverage), not just data transmissioncapacity. In light of this background, technological development andstandardization of 5th generation mobile communication systems (5G) thatwill have marked improvement in capabilities and functions as comparedwith the 4th generation mobile communication systems (4G: 4th Generationmobile communication systems) is being advanced.

In 5G standardization, the 3GPP (3rd Generation Partnership Project) isadvancing technological development of a new wireless access technology(NR: New Radio), that does not necessarily have backward-compatibilitywith LTE (Long Term Evolution)-Advanced.

An arrangement is being studied for NR, where, in the same way as withLTE, a terminal (UE: User Equipment) uses an uplink control channel(PUCCH: Physical Uplink Control Channel) to transmit response signalsindicating downlink data error detection results (ACK/NACK:Acknowledgement/Negative Acknowledgment), downlink channel stateinformation (CSI: Channel State Information), and uplink wirelessresource allocation request (SR: Scheduling Request), to a base station(eNB or gNB).

PUCCH resources in LTE as standardized by the 3GPP include frequencydomain and code domain resources (e.g., see NPL 1 through 3).Specifically, PUCCH resources in LTE are defined by resource blocks (RB:Resource Block) (may also be referred to as PRB: Physical RB) within thesystem band, and spread code (CS: Cyclic Shift or orthogonal code).PUCCH resources in LTE are made up of one PRB of frequency domain, andone subframe (14 symbols) of time domain.

CITATION LIST Non Patent Literature

NPL 1: 3GPP TS 36.211 V13.4.0, “Evolved Universal Terrestrial RadioAccess (E-UTRA); Physical channels and modulation (Release 13),”December 2016.

NPL 2: 3GPP TS 36.213 V13.4.0, “Evolved Universal Terrestrial RadioAccess (E-UTRA); Physical layer procedures (Release 13),” December 2016.

NPL 3: 3GPP TS 36.211 V13.4.0, “Evolved Universal Terrestrial RadioAccess (E-UTRA); Physical channels and modulation (Release 13), ”December 2016.

NPL 4: R1-1701553, “Final minutes from RAN1 #AH1_NR (Spokane'smeeting),” ETSI, MCC, February 2017.

NPL 5: R1-1704043, “WF on PUCCH resource allocation,” LG Electronics,NTT DOCOMO, ETRI, CATT, February 2017.

SUMMARY OF INVENTION

As described above, PUCCH resources in LTE are configured of one PRB andone subframe, with information that the base station should indicate theterminal of for allocation of PUCCH resources being frequency resources(PRB index) and spreading code index (CS index or orthogonal codeindex). However, NR handles requirements and transmission/receptioncapabilities of diverse services, so PUCCH design with higherflexibility than in LTE is necessary.

One embodiment of the present disclosure facilitates providing of a basestation, terminal, and communication method where PUCCH resources can beflexibly allocated.

A base station according to an embodiment of the present disclosureincludes: a circuit that selects, from a plurality of combinations ofparameters regarding uplink control channel (PUCCH) resources, onecombination; and a transmitter that indicates a terminal of resourcesettings corresponding to the plurality of combinations by higher layersignaling, and indicates the terminal of the one combination that hasbeen selected by dynamic signaling.

A terminal, according to an embodiment of the present disclosureincludes: a receiver that receives higher layer signaling includingresource settings corresponding to a plurality of combinations ofparameters regarding uplink control channel (PUCCH) resources, andreceives dynamic signaling indicating one combination out of theplurality of combinations; and a transmitter that transmits uplinkcontrol signals by the PUCCH resources represented by the plurality ofparameters corresponding to the one combination indicated by the dynamicsignaling, out of the plurality of combinations.

A communication method according to an embodiment of the presentdisclosure includes: selecting, from a plurality of combinations ofparameters regarding uplink control channel (PUCCH) resources, onecombination; and indicating a terminal of resource settings includingthe plurality of combinations by higher layer signaling, and indicatingthe terminal of the one combination that has been selected by dynamicsignaling.

A communication method according to an embodiment of the presentdisclosure includes: receiving higher layer signaling including resourcesettings including a plurality of combinations of parameters regardinguplink control channel (PUCCH) resources, and receiving dynamicsignaling indicating one combination out of the plurality ofcombinations; and transmitting uplink control signals by the PUCCHresources represented by the plurality of parameters corresponding tothe one combination indicated by the dynamic signaling, out of theplurality of combinations.

It should be noted that these general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, or a recording medium, and may be realized by any combinationof a system, device, method, integrated circuit, computer program, andrecording medium.

According to one embodiment of the present disclosure, PUCCH resourcescan be flexibly allocated.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to comprehend one or more of such features.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a configuration example of an NR slot.

FIG. 2 illustrates an example of PUCCH resources in LTE.

FIG. 3 illustrates types of slots.

FIG. 4 illustrates an example of PUCCH resources within a band.

FIG. 5 illustrates the configuration of a base station according to afirst embodiment.

FIG. 6 illustrates the configuration of a terminal according to thefirst embodiment.

FIG. 7 illustrates the configuration of the base station according tothe first embodiment.

FIG. 8 illustrates the configuration of the terminal according to thefirst embodiment.

FIG. 9 illustrates processing between the base station and terminalaccording to the first embodiment.

FIG. 10 illustrates an example of correlation between DCI bits andSemi-static resource configuration according to the first embodiment.

FIG. 11 illustrates an example of frequency domain resources accordingto a first modification of the first embodiment.

FIG. 12 illustrates an example of a notification method of a parameter Xat the time of Localized transmission in the first modification of thefirst embodiment.

FIG. 13 illustrates an example of a notification method of a parameter Xat the time of Distributed transmission in the first modification of thefirst embodiment.

FIG. 14 illustrates a setting example of the range of a parameterN_(offset) in the first modification of the first embodiment.

FIG. 15 illustrates an example of an RB grid among Numerologies withdifferent subcarrier spacings.

FIG. 16 illustrates a setting example of parameters M_(PRB) and Daccording to a second modification of the first embodiment.

FIG. 17A illustrates a setting example of a parameter D as to a ShortPUCCH according to a third modification of the first embodiment.

FIG. 17B illustrates a setting example of a parameter D as to a LongPUCCH according to the third modification of the first embodiment.

FIG. 18 illustrates an example of an Uplink control resource setaccording to a fifth modification of the first embodiment.

FIG. 19 describes a problem of a second embodiment.

FIG. 20A illustrates an example of transmission in slot increments.

FIG. 20B illustrates an example of transmission in slot increments.

FIG. 21 illustrates an example of transmission in non-slot increments.

FIG. 22 illustrates an example of a notification method of PUCCHresources according to a fourth embodiment.

FIG. 23 illustrates an example of a notification method of PUCCHresources according to a modification of the fourth embodiment.

FIG. 24A illustrates a setting example of PUCCH resources according to afifth embodiment.

FIG. 24B illustrates an example of correlation between DCI bits andSemi-static resource configuration according to the fifth embodiment.

FIG. 25A illustrates a setting example of PUCCH resources for slot naccording to a modification of the fifth embodiment.

FIG. 25B illustrates a setting example of PUCCH resources for slot n+1according to a modification of the fifth embodiment.

FIG. 25C illustrates a setting example of PUCCH resources for slot n+2according to a modification of the fifth embodiment.

FIG. 25D illustrates a setting example of PUCCH resources for slot n+3according to a modification of the fifth embodiment.

FIG. 26 illustrates a setting example of PUCCH resources according to asixth embodiment.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail belowwith reference to the drawings.

A terminal transmitting uplink control signals such as ACK/NACK signals(response signals), CSI, SR, and so forth, to the base station usingPUCCH in the same way as in LTE, is being studied in NR, as describedabove.

In doing so, the terminal needs to identify PUCCH resources used fortransmission of uplink control signals. A method is being studied in NRwhere, with regard to allocation PUCCH resources for transmittingACK/NACK signals in downlink data, a terminal is indicated of a set ofsemi-static (Semi-static) PUCCH resources by higher layer signals, andthe terminal selects PUCCH resources to actually be used by downlinkcontrol signals (DCI: Downlink Control Information) (e.g., see NPLs 4and 5). Now, PUCCH resources in NR include the resources of time domain,and frequency domain or code domain. Time domain resources include slotsand symbols within slots. FIG. 1 is a configuration example of slots(also referred to as “NR slot”) in NR. An NR slot is configured of sevensymbols or 14 symbols.

Next, PUCCH resources allocation in LTE standardized by the 3GPP will bedescribed (e.g., see NPLs 1 through 3). In LTE, there are frequencydomain and code domain resources for PUCCH resources. Specifically,PUCCH resources are defined by resource blocks (PRB) and spreading code(CS) in the system band, as illustrated in FIG. 2.

In LTE, PUCCH resources (PRB and spreading code) for transmittingACK/NACK signals regarding downlink data are implicitly decided fromdownlink control channel (PDCCH: Physical Downlink Control Channel)resources with corresponding downlink data allocated. For example, inthe example in FIG. 2, in a case where a PUCCH resource corresponding toa PDCCH resource is n14, a PRB with RB index #1 and spreading code of CSindex #2 are allocated.

Also, in the FDD (Frequency Division Duplex) system in LTE, ACK/NACKsignals for downlink data are transmitted using PUCCH resources in anobject subframe four subframes after the subframe where the downlinkdata was transmitted. Also, in the TDD (Time Division Duplex) system inLTE, ACK/NACK signals for downlink data are transmitted using PUCCHresources in an object subframe four or more subframes after thesubframe where the downlink data was transmitted.

That is to say, in LTE, time domain resources for transmission of PUCCH(uplink subframes) are correlated with subframes where downlink data wastransmitted, and fixed. Accordingly, there has been no need forindication of time domain resources for transmission of PUCCH to theterminal in LTE. On the other hand, there is need to indicate theterminal of the time domain resource (slot index, etc.) for transmissionof PUCCH in NR, in order to flexibly change the time domain resources(slot position) in accordance with requirements of services andprocessing capabilities of the terminal when transmitting PUCCH to theterminal.

As described earlier, the PUCCH resources are configured of one PRB inthe frequency domain and one subframe in the time domain in LTE.Accordingly, if the subframe where PUCCH is transmitted is identified,there has been no need in LTE to make indication of other information(e.g., symbol information) regarding the time domain resources fortransmission of PUCCH. On the other hand, flexibly changing thetransmission time of PUCCH in accordance with service requirements orprocessing capabilities of the terminal is being studied in NR, such asPUCCH transmission of one or two symbols, or PUCCH transmission of threeor more symbols (e.g., four or more symbols), and so forth. Accordingly,with regard to time domain resources for transmission of PUCCH, there isa need to indicate the terminal of information relating to symbolstransmitting PUCCH in one slot in NR. The terminal also has to beindicated of the PUCCH transmission period length (symbol length, etc.)in NR.

Frequency domain resources for PUCCH transmission in LTE are configuredof one PRB in LTE, so there has been the need to indicate the terminalof the position of this one PRB. On the other hand, PUCCH transmissionusing multiple PRBs is being studied in NR. Accordingly, there is a needto indicate the terminal of more resource allocation information ascompared to LTE with regard to frequency domain resource for PUCCHtransmission as well in NR.

Thus, there is an increase of parameters necessary for indication ofPUCCH resource allocation in NR as compared to LTE, with regard to bothtime domain resources and frequency domain resources.

As described above, a method is being studied regarding allocation ofPUCCH resources for transmission of ACK/NACK signals for downlink datain NR, where the base station makes indication of a set of semi-staticPUCCH resources by higher layer signals, and PUCCH resources to actuallybe used by DCI are selected.

However, there is an increase in parameters necessary for indication ofallocation of PUCCH resources in NR as compared to LTE, as describedabove. Accordingly, in a case of indicating the terminal of values thateach of the parameters of the PUCCH resources can assume by higher layersignals, and selecting values of PUCCH resources to actually be used byDCI, the number of parameters to be indicated by DCI increases, and theDCI overhead increases.

On the other hand, in LTE, PUCCH resources for transmitting CSI or SRsare semi-statically and explicitly indicated by higher layer signals. Amethod is also employed in LTE where, with regard to PUCCH resourceallocation for transmission of ACK/NACK signals indicating errordetection results of downlink data using SPS (Semi-persistentscheduling) or the like, the base station semi-statically indicates theterminal of multiple PUCCH resources (e.g., four PUCCH resources) byhigher layer signals, and one PUCCH resource to be actually used isselected out of the multiple PUCCH resources, using two bits of thedownlink control signals (DCI) of the PDCCH to which correspondingdownlink data has been allocated.

However, in a case of semi-statically indicating the terminal ofmultiple PUCCH resources by higher layer signals, and selecting onePUCCH resource to be actually used by several bits of the DCI of thePDCCH to which the corresponding downlink data has been allocated, as inthe indication method of SPS resource allocation in LTE, the number ofDCI bits can be reduced, but flexible resource allocation cannot berealized.

Also, in a case of extending the method in LTE for NR, the PUCCHresource (slot position, symbol position, RB index, etc.,) can beidentified, but PUCCH transmission length and resource mapping of thefrequency domain have not been taken into consideration.

Accordingly, description will be made below regarding a method wherePUCCH resources can be appropriately allocated in NR while preventingincreased DCI overhead.

In PUCCH resources allocation in NR, all combinations of time domainresources and frequency domain resources do not have to be taken intoconsideration. For example, the number of symbols in a slot that can beused as PUCCH resources are dependent on the type of slot (Downlinkcentric slot, Uplink centric slot, Downlink only slot, Uplink only slot,and so forth) in NR, as illustrated in FIG. 3.

For example, in the example in FIG. 3, the number of symbols in a slotthat can be used as PUCCH resources (UL symbols) are a maximum of twosymbols in the case of Downlink centric slot, a maximum of five symbolsin the case of Uplink centric slot, zero symbols in the case of Downlinkonly slot, and a maximum of seven symbols in the case of Uplink onlyslot. Thus, the number of symbols within the slot are dependent on thetype of slot, so not all combinations of parameters relating to slotsand parameters relating to symbols have to be taken into considerationas PUCCH resources.

Also, it is also conceivable that the number of symbols within a slotthat can be used as PUCCH resources is dependent on frequency resources(PRB) within the system band or a band allocable to a terminal, asillustrated in FIG. 4.

For example, in the example in FIG. 4, at the PRBs of RB index #0through #3, two symbols (symbol #5 and #6) are usable as PUCCHresources, and at the PRBs of RB index #N-4 through #N-1, five symbols(symbol #2 through #6) are usable as PUCCH resources. Thus, the numberof symbols within the slot differ depending on the frequency band, sothere is no need to take into consideration all combinations ofparameters relating to frequency resources (RB indices.) and parametersrelating to symbols as PUCCH resources.

Further, the PUCCH transmission length (number of symbols) is dependenton symbol positions within the slot. For example, a PUCCH transmittedusing two symbols will never be combined with symbol #6 (e.g., the lastsymbol in the slot). Also, for a PUCCH transmitted using four symbols,for example, combination with Downlink centric slot (two UL symbols) andDownlink only slot (zero UL symbols) illustrated in FIG. 3, or the RBindices. #0 through #3 (two UL symbols) illustrated in FIG. 4 does nothave to be taken into consideration.

Thus, there is no need in NR to take into consideration all combinationsof time domain resources and frequency domain resources in allocation ofPUCCH resources.

Accordingly, in one embodiment of the present disclosure, with regard toallocation of PUCCH resources for transmission of uplink control signals(e.g., ACK/NACK signals), the base station makes indication to theterminal of resource settings including combinations of multipleparameters relating to PUCCH resources (defined as “Semi-static resourceconfiguration”) using higher layer signals, and one combination ofparameters regarding the PUCCH resource to be actually used is selectedusing several bits of the DCI of the PDCCH to which correspondingdownlink data has been allocated.

At this time, an example of parameters (Semi-static resourceconfiguration) relating to PUCCH resources that the base stationindicates the terminal of by higher layer signals includes informationrelating to usage of frequency domain resources (hereinafter expressedas X(0), X(1), . . . , X(N_(X)−1)), information relating to time domainresources (specifically, slots) (hereinafter expressed as A(0), A(1), .. . , A(N_(A)−1)), information relating to time domain resources(specifically, symbol positions within slots) (hereinafter expressed asB(0), B(1), . . . , B(N_(B)−1)), and information related to PUCCHtransmission period (hereinafter expressed as C(0), C(1), . . . ,C(N_(C)−1)). Note that parameters related to PUCCH resources are notrestricted to this information.

Differences in PUCCH resources used by the terminal are generated bycombinations of the parameters (X, A, B, and C) in the Semi-staticresource configuration that the base station indicates the terminal ofby higher layer signals.

Thus, multiple parameter combinations relating to PUCCH resources areindicated to the terminal from the base station by higher layer signals,and the combination actually used is indicated by DCI, so increase inDCI overhead can be prevented as compared to a case of the multipleparameters themselves to be actually used being indicated by DCI. Also,combinations that can be set as PUCCH resources are indicated by higherlayer signals, rather than all combinations of multiple parametersrelating to PUCCH resources, and the combination to be actually used isindicated by DCI, whereby flexible allocation of PUCCH resources can berealized.

Embodiments will be described below in detail.

As one example of granularity (unit) of PUCCH resources, the frequencydomain will be described hereinafter in increments of PRBs and the timedomain in unit of symbols. That is to say, assumption is made thatPUCCHs among different terminals are subjected to FDM in PRB domain, andTDM in units of symbols. Note that the granularity (unit) of PUCCHresources is not restricted to this.

First Embodiment [Overview of Communication System]

A communication system according embodiments of the present disclosurehave a base station 100 and a terminal 200.

FIG. 5 is a block diagram illustrating the configuration of the basestation 100 according to the embodiments of the present disclosure. Inthe base station 100 illustrated in FIG. 5, a control unit 101 selectsone combination from multiple combinations of parameters relating touplink control channel (PUCCH) resources. A transmission unit 114indicates the terminal 200 of resource settings (Semi-static resourceconfiguration) that the multiple combinations indicate by higher layersignaling, and indicates the terminal 200 of the one combination thathas been selected, by dynamic signaling (DCI).

FIG. 6 is a block diagram illustrating the configuration of the terminal200 according to the embodiments of the present disclosure. In theterminal 200 illustrated in FIG. 6, a reception unit 202 receives higherlayer signaling including resource settings (Semi-static resourceconfiguration) indicating multiple parameter combinations relating touplink control channel (PUCCH) resources, and receives dynamic signaling(DCI) indicating one combination of the multiple combinations. Atransmission unit 219 transmits uplink control signals by PUCCHresources represented by multiple parameters corresponding to the onecombination out of the multiple combinations that is indicated bydynamic signaling.

[Configuration of Base Station]

FIG. 7 is a block diagram illustrating the configuration of the basestation 100 according to a first embodiment of the present disclosure.In FIG. 7, the base station 100 includes the control unit 101, a datagenerating unit 102, an encoding unit 103, a retransmission control unit104, a modulating unit 105, an higher layer control signal generatingunit 106, an encoding unit 107, a modulating unit 108, a downlinkcontrol signal generating unit 109, an encoding unit 110, a modulatingunit 111, a signal allocation unit 112, an IFFT (Inverse Fast FourierTransform) unit 113, a transmission unit 114, an antenna 115, areception unit 116, an FFT (Fast Fourier Transform) unit 117, anextracting unit 118, a CSI demodulating unit 119, an SRS (SoundingReference Signal) measuring unit 120, a modulating/demodulating unit121, and a determining unit 122.

The control unit 101 determines the “Semi-static resource configuration”including the multiple parameter combinations regarding uplink resourcesto be indicated to the terminal 200 by higher layer signals. The uplinkresources here are, for example, PUCCH resources for transmittingACK/NACK signals, PUCCH resources for transmitting periodic CSI signals,PUCCH resources for transmitting SRs, PUCCH resources for transmittingaperiodic CSI signals, resources for transmitting periodic and aperiodicSRS signals, and so forth. The control unit 101 outputs the informationthat has been decided to the higher layer control signal generating unit106.

The control unit 101 decides an uplink resource to be actually allocatedto the terminal 200 (i.e., a combination of parameters to be indicatedby DCI), out of the Semi-static resource configuration indicated to theterminal 200 by higher layer signals. For example, the control unit 101decides information relating to actual resources for indication by DCIfrom each of PUCCH resources configuration for transmitting ACK/NACKsignals, resource configuration for transmitting Aperiodic CSI signals,and resource configuration for transmitting Aperiodic SRS, that areincluded in the Semi-static resource configuration. The control unit 101outputs the decided information to the downlink control signalgenerating unit 109. The control unit 101 also outputs the decidedinformation to the extracting unit 118, to correctly receive signalsfrom the terminal 200.

The control unit 101 also decides wireless resource allocation regardingdownlink data to the terminal 200, and outputs downward resourceallocation information indicating resource allocation for downlink datato the downlink control signal generating unit 109 and signal allocationunit 112.

The data generating unit 102 generates downlink data for the terminal200, and outputs to the encoding unit 103.

The encoding unit 103 performs error correction encoding processing onthe downlink data input from the data generating unit 102, and outputsthe encoded data signals to the retransmission control unit 104.

At the time of initial transmission, the retransmission control unit 104stores the encoded data signals input from the encoding unit 103, andalso outputs to the modulating unit 105. Upon a NACK being input fromthe later-described determining unit 122 in response to the transmitteddata signals, the retransmission control unit 104 outputs thecorresponding data that is stored to the modulating unit 105. On theother hand, upon an ACK being input from the determining unit 122 inresponse to the transmitted data signals, the retransmission controlunit 104 deletes the corresponding data that is stored.

The modulating unit 105 modulates the data signals input from theretransmission control unit 104, and outputs the data modulation signalsto the signal allocation unit 112.

The higher layer control signal generating unit 106 uses the informationinput from the control unit 101 (e.g., Semi-static resourceconfiguration) to generate a control information bit string, and outputsthe generated control information bit string to the encoding unit 107.

The encoding unit 107 performs error correction encoding on the controlinformation bit string input from the higher layer control signalgenerating unit 106, and outputs the encoded control signals to themodulating unit 108.

The modulating unit 108 modulates the control signals input from theencoding unit 107, and outputs the modulated control signals to thesignal allocation unit 112.

The downlink control signal generating unit 109 generates a controlinformation bit string (DCI) using information input from the controlunit 101 (information relating to the uplink resource that the terminal200 will actually use, and downlink resource allocation information),and outputs the generated control information bit string to the encodingunit 110. Note that there are cases where control information istransmitted to multiple terminals, so the downlink control signalgenerating unit 109 may generate a bit string including the terminal IDof each terminal in the control information for the terminals.

The downlink control signal generating unit 109 may also generate agroup common control information bit string address to the multipleterminals, using information instructing slot type or resource amount(number of symbols, etc.) usable for uplink.

The encoding unit 110 performs error correction encoding on the controlinformation bit string input from the downlink control signal generatingunit 109, and outputs the encoded control signals to the modulating unit111.

The modulating unit 111 modulates the control signals input from theencoding unit 110 and outputs the modulated control signals to thesignal allocation unit 112.

The signal allocation unit 112 maps the data signals input from themodulating unit 105 to wireless resources, based on downward resourceallocation information input from the control unit 101. The signalallocation unit 112 also maps control signals input from the modulatingunit 108 or modulating unit 111 to wireless resources. The signalallocation unit 112 outputs the downlink signals where signals have beenmapped to the IFFT unit 113.

The IFFT unit 113 subjects the signals input from the signal allocationunit 112 to transmission waveform generating processing such as OFDM(Orthogonal Frequency Division Multiplexing) or the like. In a case ofOFDM transmission where a CP (Cyclic Prefix) is attached, the IFFT unit113 attaches the CP (omitted from illustration). The IFFT unit 113outputs the generated transmission waveforms to the transmission unit114.

The transmission unit 114 performs RF (Radio Frequency) processing suchas D/A (Digital-to-Analog) conversion, upconverting, and so forth, onthe signals input from the IFFT unit 113, and transmits the wirelesssignals to the terminal 200 via the antenna 115.

The reception unit 116 performs RF processing such as downconverting orND (Analog-to-Digital) conversion and the like on uplink signalwaveforms from the terminal 200 received via the antenna 115, andoutputs the uplink signal waveforms after reception processing to theFFT unit 117.

The FFT unit 117 subjects the uplink signal waveforms input from thereception unit 116 to FFT processing for conversion of time domainsignals into frequency domain signals. The FFT unit 117 outputs thefrequency domain signals obtained by FFT processing to the extractingunit 118.

The extracting unit 118 extracts wireless resources where CSI feedbacksignals, SRS, or ACK/NACK signals have been transmitted, from thesignals input from the FFT unit 117, based on information received fromthe control unit 101 (information relating to uplink resources actuallyallocated at the terminal 200), and outputs the components of thewireless resources that have been extracted (CSI feedback signals, SRS,or ACK/NACK signals) to the CSI demodulating unit 119, SRS measuringunit 120, or modulating/demodulating unit 121, respectively.

The CSI demodulating unit 119 demodulates the CSI feedback signals inputfrom the extracting unit 118, and outputs the demodulated information tothe control unit 101. The CSI feedback is used by the control unit 101for downlink allocation control, for example.

The SRS measuring unit 120 uses SRS signals input from the extractingunit 118 to measure the uplink channel quality, and outputs measurementinformation to the control unit 101. The information of the measurementis used at the control unit 101 for uplink allocation control (omittedfrom illustration), for example.

The modulating/demodulating unit 121 performs demodulation and errorcorrection decoding on the signals input from the extracting unit 118,and outputs a decoded bit string to the determining unit 122.

The determining unit 122 determines which of ACK and NACK that theACK/NACK signal transmitted from the terminal 200 indicates with regardto the transmitted data signals, based on the bit string input from themodulating/demodulating unit 121. The determining unit 122 outputs theresults of the determination to the retransmission control unit 104.

[Configuration of Terminal]

FIG. 8 is a block diagram illustrating the configuration of the terminal200 according to the first embodiment of the present disclosure. In FIG.8, the terminal 200 includes an antenna 201, the reception unit 202, anFFT unit 203, an extracting unit 204, a downlink control signaldemodulating unit 205, an higher layer control signal demodulating unit206, a downlink data signal demodulating unit 207, an error detectingunit 208, a control unit 209, a CSI generating unit 210, an encodingunit 211, a modulating unit 212, an ACK/NACK generating unit 213, anencoding unit 214, a modulating unit 215, an SRS generating unit 216, asignal allocation unit 217, an IFFT unit 218, and the transmission unit219.

The reception unit 202 subjects signal waveforms of downlink signals(data signals and control signals) received from the base station 100via the antenna 201 to RF processing such as downconversion and A/D(Analog-to-Digital) conversion, and outputs the obtained receptionsignals (baseband signals) to the FFT unit 203.

The FFT unit 203 subjects the signals (dime domain signals) input fromthe reception unit 202 to FFT processing, where time domain signals areconverted into frequency domain signals. The FFT unit 203 outputs thefrequency domain signals obtained by the FFT processing to theextracting unit 204.

The extracting unit 204 extracts downlink control signals (DCI) fromsignals input from the FFT unit 203, based on control information inputfrom the control unit 209, and outputs to the downlink control signaldemodulating unit 205. The extracting unit 204 also extracts higherlayer control signals and downlink data signals based on controlinformation input from the control unit 209, outputs higher layercontrol signals to the higher layer control signal demodulating unit206, and outputs downlink data signals to the downlink data signaldemodulating unit 207.

The downlink control signal demodulating unit 205 performs blinddecoding of the downlink control signals input from the extracting unit204, and in a case of judging that these are control signals addressedto itself, demodulates these control signals and outputs to the controlunit 209.

The higher layer control signal demodulating unit 206 demodulates thehigher layer control signals input from the extracting unit 204, andoutputs the demodulated higher layer control signals to the control unit209.

The downlink data signal demodulating unit 207 demodulates and decodesdownlink data signals input from the extracting unit 204, and outputsdecoded downlink data to the error detecting unit 208.

The error detecting unit 208 performs error detection on the downlinkdata input from the downlink data signal demodulating unit 207, andoutputs error detection results to the ACK/NACK generating unit 213. Theerror detecting unit 208 also outputs downlink data that has beendetermined to be without error as reception data as a result of errordetection.

The control unit 209 calculates wireless resource allocation for thedownlink data signals based on downlink resource allocation informationindicated in control signals input from the downlink control signaldemodulating unit 205, and outputs information indicating the calculatedwireless resource allocation to the extracting unit 204.

The control unit 209 also uses higher layer control signals (Semi-staticresource configuration) input from the higher layer control signaldemodulating unit 206 and control signals (information relating touplink resources to be actually used by the terminal 200) input from thedownlink control signal demodulating unit 205 to set the uplinkresources (PUCCH resources for transmitting ACK/NACK signals, PUCCHresources for transmitting Periodic CSI signals, PUCCH resources fortransmitting SRs, resources for transmitting Aperiodic CSI signals, andresources for transmitting Periodic and Aperiodic SRS) that the terminal200 is to use by a method which will be described later. The controlunit 209 then outputs the information regarding uplink resources thathas been set to the signal allocation unit 217.

The CSI generating unit 210 uses measurement results (omitted fromillustration) of downlink channel quality measured at the terminal 200to generate a CSI feedback bit string, and outputs the CSI feedback bitstring to the encoding unit 211.

The encoding unit 211 performs error correction encoding on the CSIfeedback bit string input from the CSI generating unit 210, and outputsthe encoded CSI signals to the modulating unit 212.

The modulating unit 212 modulates the CSI signals input from theencoding unit 211, and outputs the modulated CSI signals to the signalallocation unit 217.

The ACK/NACK generating unit 213 generates ACK/NACK signals (ACK orNACK) as to the received downlink data, based on the error detectionresults input from the error detecting unit 208. The ACK/NACK generatingunit 213 outputs the generated ACK/NACK signals (bit series) to theencoding unit 214.

The encoding unit 214 performs error correction encoding to the bitseries input from the ACK/NACK generating unit 213, and outputs theencoded bit series (ACK/NACK signals) to the modulating unit 215.

The modulating unit 215 modulates the ACK/NACK signals input from theencoding unit 214 and outputs the modulated ACK/NACK signals to thesignal allocation unit 217.

The SRS generating unit 216 generates an SRS series and outputs to thesignal allocation unit 217.

The signal allocation unit 217 maps each of the CSI signals input fromthe modulating unit 212, ACK/NACK signals input from the modulating unit215, and SRS series input from the SRS generating unit 216, to wirelessresources instructed by the control unit 209. The signal allocation unit217 outputs uplink signals where the signals have been mapped to theIFFT unit 218.

The IFFT unit 218 subjects the signals input from the signal allocationunit 217 to transmission wave generation processing such as OFDM or thelike. In a case of OFDM transmission where a CP (Cyclic Prefix) isattached, the IFFT unit 218 attaches the CP (omitted from illustration).Alternatively, in a case where the IFFT unit 218 generatessingle-carrier waveforms, a DFT (Discrete Fourier Transform) unit may beadded (omitted from illustration) upstream of the signal allocation unit217. The IFFT unit 218 outputs the generated transmission waveforms tothe transmission unit 219.

The transmission unit 219 performs RF (Radio Frequency) processing suchas D/A (Digital-to-Analog) conversion, upconverting, and so forth, onthe signals input from the IFFT unit 218, and transmits the wirelesssignals to the base station 100 via the antenna 201.

[Operations of the Base Station 100 and Terminal 200]

Operations at the base station 100 and terminal 200 having the aboveconfigurations will be described below in detail.

FIG. 9 illustrates the flow of processing at the base station 100 andterminal 200 according to the present embodiment.

The base station 100 indicates the terminal 200 of a synchronizationsignal (PSS (Primary Synchronization Signal)/SSS (SecondarySynchronization Signal)) or system information (MIB (Master InformationBlock)/SIB (System Information Block)) (ST101). The terminal 200 obtainsthe synchronization signal or system information (ST102).

Next, the base station 100 decides resource initial-access settings(Semi-static resource configuration) for the terminal 200 (ST103), andtransmits the Semi-static resource configuration that has been decidedto the terminal as cell-specific information or group-specificinformation (ST104). The terminal 200 obtains the Semi-static resourceconfiguration transmitted from the base station 100 (ST105).

The terminal 200 then executes initial access (random access) procedures(or RRC connection control) or the like with the base station 100(ST106).

Next, the base station 100 decides resource settings (Semi-staticresource configuration) specific for the terminal 200 (ST107).

For example, the parameters making up the Semi-static resourceconfiguration for PUCCH include the following information.

X: information relating to using frequency domain resources

A: information relating to time domain resources (e.g., slot)

B: information relating to time domain resources (e.g., position ofsymbol within slot)

C: information relating to PUCCH transmission period

An example of the information X relating to use of frequency domainresources is a parameter indicating the PRB used for PUCCH transmission.

An example of information A relating to time domain resources (e.g.,slot) is a parameter relating to the number of slots in PDCCH receptionwhere corresponding downlink data has been allocated.

An example of information B relating to time domain resources (e.g.,position of symbol within slot) is a parameter indicating the symbolindex (information indicating what symbol index from the end (or thestart) is to be started from) within a slot for starting PUCCHtransmission.

An example of information C relating to PUCCH transmission period is aparameter indicating the number of symbols used for PUCCH transmission.

That is to say, frequency domain resources (PRB) and time domainresources (slot and symbol) for PUCCH are identified by the combinationof the parameters X, A, B, and C. Note that the parameters X, A, B, andC are not restricted to the above example.

The base station 100 sets the multiple parameters X, A, B, and C makingup the above-described Semi-static resource configuration for PUCCH, andcombinations of parameters X, A, B, and C, as illustrated in FIG. 10,for example. In FIG. 10, the base station 100 sets (M+1) combinations(M=N_(X)=N_(A)=N_(B)=N_(C)) regarding the parameters X, A, B, and C.

The base station 100 then transmits the decided resource settings(Semi-static resource configuration) specific to the terminal 200, tothe terminal 200, by higher layer signals (higher layer signaling)(ST108).

For example, the base station 100 indicates the terminal 200 ofinformation relating to usage of frequency domain resources (X(0), X(1),. . . , X(N_(X))), information relating to time domain resources (slots)(A(0), A(1), . . . , A(N_(A))), information relating to time domainresources (symbol positions within slots) (B(0), B(1), . . . ,B(N_(B))), and information regarding PUCCH transmission period (C(0),C(1), . . . , C(N_(C))), by higher layer signals, as Semi-staticresource configuration for PUCCH indicating (M+1) combinations(combinations corresponding to DCI bits which will be described later)illustrated in FIG. 10.

The base station 100 indicates the terminal 200 of the associationbetween the Semi-static resource configuration and DCI bits (e.g., seeFIG. 10) by higher layer signals.

The terminal 200 obtains resource settings included in the higher layersignals (ST109). Accordingly, the terminal 200 identifies multiple (M+1)combinations that can be set as frequency domain resources and timedomain resources for PUCCH, by obtaining the Semi-static resourceconfiguration for PUCCH by the higher layer signals from the basestation 100.

Next, the base station 100 decides information relating to uplinkresources or downlink resources to be actually allocated to the terminal200 (uplink resource information to be notified by DCI) (ST110). At thistime, the base station 100 selects one combination of parameters to beactually used with regard to the terminal 200, out of the Semi-staticresource configuration (combination of parameters relating to uplinkresources) that the terminal 200 was indicated of by higher layersignals in ST108.

The base station 100 then transmits the decided uplink resourceinformation (the one combination that has been selected), downlinkresource allocation information of downlink data, and this downlinkdata, to the terminal 200 (ST111). That is to say, the base station 100indicates the terminal 200 of the one combination corresponding to theresources to be actually used out of (M+1) combinations of parameters X,A, B, and C illustrated in FIG. 10, by DCI bits of the PDCCH to whichthe corresponding downlink data is allocated (dynamic signaling).

The terminal 200 obtains uplink resource information (the combination ofparameters selected at the base station 100) (ST112).

The terminal 200 then performs CRC (Cyclic Redundancy Check) on thedownlink data, for example, and feeds back to the base station 100 anACK if there is no error in the CRC computation results, or a NACK ifthere is error in the CRC computation results, as ACK/NACK signals(ST113). At this time, the terminal 200 identifies resources for thePUCCH to be used for feedback of ACK/NACK signals, using one combination(X, A, B, C) indicated by DCI bits, out of the correlation (see FIG. 10)between Semi-static resource configuration for the PUCCH indicated byhigher layer signals and DCI bits.

Note that the terminal 200 can transmit the other uplink signals (CSI,SRS, SR) using the resources identified by one combination (X, A, B, C)indicated by DCI bits, out of the association (see FIG. 10) betweenSemi-static resource configuration and DCI bits, in the same way asACK/NACK signals. At this time, the association between Semi-staticresource configuration and DCI bits may differ among the signals(ACK/NACK signals, CSI, SRS, and SR).

Thus, according to the present embodiment, when indicating the terminal200 of PUCCH resource allocation information, the base station 100 makesindication of Semi-static resource configuration including multipleparameter (X, A, B, C) combinations relating to PUCCH resources usinghigher layer signaling, and makes indication of one combination to beactually used for allocation to the terminal 200 by DCI. That is to say,indication of PUCCH allocation is performed using higher layer signalingand DCI in conjunction.

The terminal 200 then transmits the uplink control signals (ACK/NACKsignals CSI, SRS, and SR) by PUCCH resources represented by the multipleparameters corresponding to the one combination indicated by DCI, out ofthe Semi-static resource configuration indicated by higher layersignaling.

Accordingly, it is sufficient for the base station 100 to makeindication of one combination (bit information) by DCI at the time ofPUCCH allocation, and the need to make indication of PUCCH resources tobe actually used (information X, A, B, and C relating to frequencydomain resources and time domain resources) each time PUCCH allocationis performed, so increase in the DCI size can be suppressed.

Also, the base station 100 can make indication of PUCCH resources madeup of multiple combinations of frequency domain resources and timedomain resources as a Semi-static resource configuration by higherlayer, and by using DCI can dynamically change the combination that theterminal 200 will actually use out of the multiple combinations of PUCCHresources, so PUCCH resources can be flexibly allocated.

Thus, according to the present embodiment, PUCCH resources can beflexibly allocated while preventing increase in DCI overhead.

First Modification of First Embodiment

A indication method of information X regarding use of frequency domainresources will be described.

As one indication method of information (X(0), X(1), . . . , X(N_(X)))regarding use of frequency domain resources, a method by bitmap isconceivable. A method using bitmap enables flexible resource allocationto be realized, but overhead for indicating the information X regardinguse of frequency domain resources by higher layer signals increases. Forexample, in a case where the number of PRBs corresponding to thebandwidth is N_(RB), N_(RB) bits are necessary for indicating theinformation X regarding use of frequency domain resources by bitmap.

With regard to PUCCH resources mapping, supporting Localizedtransmission and Distributed transmission is begin studied in NR.

In this case, information X regarding use of frequency domain resourcescan be expressed using the four parameters of start position (offsetvalue) starting from the edge of the band (system band or band allocableto the terminal 200) (N_(offset)), number of consecutive PRBs (M_(PRB)),number of clusters (N_(cluster)), and inter-cluster distance (D).

FIG. 11 illustrates an example in a case of configuring information(X(0), X(1), . . . , X(N_(X))) regarding use of frequency domainresources using the above four parameters. In FIG. 11, the number ofPRBs in the band is N_(RB)=32 and N_(X)=7.

In this case, 32 bits would be necessary to make indication regardingthe information X regarding use of frequency domain resources by bitmap.

On the other hand, in a case of using the above four parameters in theLocalized transmission illustrated in FIG. 11, indication of (X(0),X(1), . . . , X(7)) is made as illustrated in FIG. 12. Also, in a caseof using the above four parameters in the Distributed transmissionillustrated in FIG. 11, notification of (X(0), X(1), . . . , X(7)) ismade as illustrated in FIG. 13.

At this time, the maximum number of bits necessary for indicationregarding each of the four parameters is log₂ 32=5 bits. Thus, thenumber of bits necessary for indication of the information X regardinguse of frequency domain resources is 20 bits.

According to the above, configuring the information (X(0), X(1), . . . ,X(N_(X)−1)) regarding use of frequency domain resources using the fourparameters of start position starting from the edge of the band(N_(offset)), number of consecutive PRBs (M_(PRB)), cluster count(N_(cluster)), and inter-cluster distance (D), as in the firstmodification, enables indication by both mapping methods of Localizedtransmission and Distributed transmission, and the number of bitsnecessary for indication of the information X regarding use of frequencydomain resources can be reduced.

Further, in the first modification, restrictions are applied to therange of values that the parameters configuring the information Xregarding use of frequency domain resources can assume, thereby enablingfurther reduction in the number of bits necessary for indication of theinformation X regarding use of frequency domain resources, and reductionin the number of candidates for the information regarding use offrequency domain resources (X(0), X(1), . . . , X(N_(X))), as shownbelow.

<Start Position (N_(offset)) from Edge of Band (System Band or BandAllocable to Terminal 200)

Cases are assumed in NR where the bandwidth that the terminal 200supports and the system band differ, with the bandwidth that theterminal 200 supports being narrower than the system bandwidth.

In this case, the start position from the edge of the band (N_(offset))may use the edge of the band that the terminal 200 supports as areference, as illustrated in FIG. 14. The range of values of the startposition from the edge of the band (N_(offset)) may also be the range ofthe bandwidth that the terminal 200 supports.

Also, NR supports Short PUCCH where PUCCH is transmitted using onesymbol or two symbols, and Long PUCCH where PUCCH is transmitted usingthree or more symbols, for example. Applying frequency hopping withinthe slot to obtain frequency diversity effects is being studiedregarding Long PUCCH. Accordingly, in a case of assuming applyingfrequency hopping symmetrically as to the middle frequency of the systemband or the band that the terminal 200 supports, it is sufficient forthe range of values from the start position from the edge of the band(N_(offset)) to be a range of half the bandwidth of the system band orthe band of the band that the terminal 200 supports.

Thus, restricting the range of the value for the start position from theedge of the band (N_(offset)) enables the necessary number of bits tomake indication of the start position from the edge of the band(N_(offset)) to be reduced.

<Consecutive Number of PRBs (M_(PRB))>

The object of applying Long PUCCH that uses symbols of three or moresymbols is extended coverage. Accordingly, from the perspective of usingresources used for PUCCH transmission, it is more important to increasetime domain resources for Long PUCCH than increase frequency domainresources. Making the smallest unit of PUCCH resources in the frequencydomain to be one PRB is being studied for Long PUCCH.

Accordingly, number of consecutive PRBs (M_(PRB))=1 can always be setfor Long PUCCH.

Also, stipulating multiple PUCCH formats in accordance with the numberof bits transmitted by the PUCCH is being studied in NR. In this case,the terminal 200 can identify the number of consecutive PRBs (M_(PRB))by the PUCCH format that has been set, even if the number of consecutivePRBs (M_(PRB)) is not indicated as the parameter X.

Also, settings where the number of consecutive PRBs (M_(PRB))=2 orgreater enables effects of improved PUCCH transmission characteristicsto be obtained by channel estimation using multiple PRBs. Accordingly,settings where the number of consecutive PRBs (M_(PRB))=2 or greater isconceivable in NR. That is to say, 1 (one PRB) can be excluded from therange of values of the number of consecutive PRBs (M_(PRB)).

Thus, limiting the range of values of the number of consecutive PRBs(M_(PRB)) enables the number of bits necessary for indication of thenumber of consecutive PRBs (M_(PRB)) to be reduced.

<Number of Clusters (N_(cluster))>

As described above, from the perspective of using resources used forPUCCH transmission, it is more important to increase time domainresources for Long PUCCH than increase frequency domain resources.Making the smallest unit of PUCCH resources in the frequency domain tobe one PRB is being studied. Also, increasing the number of clustersraises the transmission power to average power ratio.

Accordingly, number of clusters (N_(cluster))=1 can always be set forLong PUCCH.

Obtaining frequency diversity effects by Distributed transmission isbeing studied regarding Short PUCCH. Note however, that frequencydifference among clusters is more important than number of clusters forfrequency diversity effects. Accordingly, a large number of clustersdoes not need to be used in PUCCH transmission. For example, this can berestricted to around number of clusters (N_(cluster))=4. Further, numberof clusters (N_(cluster))=2 can always be set. Note that the value towhich the number of clusters (N_(cluster)) is limited is not restrictedto 2 or 4, and may be other values.

Thus, limiting the range of values of the number of clusters(N_(cluster)) enables the number of bits necessary for indication of thenumber of clusters (N_(cluster)) to be reduced.

<Inter-Cluster Distance (D)>

The inter-cluster distance D may assume a value related to the bandwidthand number of consecutive PRBs (M_(PRB)). For example, in a case wherethe number of PRBs in the band is N_(PRB), the inter-cluster distance Dcan be expressed as D=N_(PRB)/M_(PRB). That is to say, the terminal 200is capable of identifying the bandwidth (N_(PRB)) and number ofconsecutive PRBs (M_(PRB)) even without being indicated of theinter-cluster distance D as parameter X.

Thus, the number of bits necessary for indication of the inter-clusterdistance D can be reduced.

As described above, applying restrictions to the range of values thatthe parameters configuring the information (X(0), X(1), . . . ,X(N_(X))) regarding use of frequency domain resources can assume enablesfurther reduction in the number of bits necessary for indication of theinformation X regarding use of frequency domain resources, and reductionin the number of candidates for the information X regarding use offrequency domain resources.

Second Modification of First Embodiment

Description will be made regarding number of consecutive PRBs (M_(PRB))and the inter-cluster distance (D) making up the information X regardinguse of frequency domain resources.

Mixed numerology, where signal waveforms of different subcarrierspacings or the like coexist in the same band is being studied in NR, asa method to enable accommodation of services with differentrequirements.

There is also being studied in NR configuring a PRB of 12 subcarriersregardless of subcarrier spacing. Agreement has been reached in the 3GPPthat, in a case of frequency division multiplexing (FDM: FrequencyDivision Multiplexing) of Numerology having different subcarrierspacings, the RB grid among the subcarrier spacings is the Nestedstructure illustrated in FIG. 15. Note that the assignment of RB gridindices. illustrated in FIG. 15 is one example, and not restrictive.

In the second modification, the number of consecutive PRBs (M_(PRB)) andinter-cluster distance (D) are set to a power of 2 in a case whereterminals 200 with different subcarrier spacings coexist.

Setting the number of consecutive PRBs (M_(PRB)) and inter-clusterdistance (D) to a power of 2 enables the clusters and boundaries of RBgrids to be aligned among Numerologies of different subcarrier spacings,so resources can be efficiently used, as illustrated in FIG. 16, forexample. Note that FIG. 16 illustrates an RB grid example where aterminal 200 having a certain subcarrier spacing (15 kHz here) and aterminal 200 having a subcarrier spacing that is double (30 kHz) aremultiplexed. Also, although both the number of consecutive PRBs(M_(PRB)) and inter-cluster distance (D) are set to four PRBs (=2²) inFIG. 16 as one example, the M_(PRB) and inter-cluster distance D may beanother power of 2 value, and may be different from each other.

Also, if the inter-cluster distance is set to D=N_(PRB)/M_(PRB), thenumber of PRBs within the band can also be made to be a power of 2.

Further, an arrangement may be made where the number of consecutive PRBs(M_(PRB)) and inter-cluster distance (D) respectively are (M_(PRB, 0))and inter-cluster distance (D₀) in a subcarrier spacing that is areference (reference subcarrier spacing), and the terminal 200identifies each of the number of consecutive PRBs (M_(PRB)) andinter-cluster distance (D) at another subcarrier spacing from the numberof consecutive PRBs (M_(PRB)) and inter-cluster distance (D) at thereference subcarrier spacing.

For example, the number of consecutive PRBs (M_(PRB)) and inter-clusterdistance (D) at another subcarrier spacing may be set to be the same asthe number of consecutive PRBs (M_(PRB, 0)) and inter-cluster distance(D₀) at the reference subcarrier spacing. Alternatively, the frequencybandwidth of the number of consecutive PRBs and inter-cluster distancemay be made to be the same among different subcarrier spacings, bysetting the number of consecutive PRBs (M_(PRB)) and inter-clusterdistance (D) at another subcarrier spacing=f₀×2^(N) (where f₀ is thereference subcarrier spacing) to be M_(PRB, 0)/N and D₀/N, respectively.

Thus, setting the number of consecutive PRBs (M_(PRB)) and inter-clusterdistance (D) to be a power of 2 enables resources to be efficientlyused, and this does away with the need to set the number of consecutivePRBs (M_(PRB)) and inter-cluster distance (D) for each differentNumerology.

Third Modification of First Embodiment

The parameter (D) making up the information X regarding use of frequencydomain resources will be described.

NR supports Short PUCCH where PUCCH is transmitted using one symbol ortwo symbols, and Long PUCCH where PUCCH is transmitted using three ormore symbols, as described above.

Obtaining frequency diversity effects by Distributed transmission isbeing studied regarding Short PUCCH. On the other hand, applyingfrequency hopping within the slot to obtain frequency diversity effectsis being studied regarding Long PUCCH. Also, applying Localizedtransmission to Long PUCCH instead of applying cluster transmission(i.e., Distributed transmission) is conceivable.

Accordingly, in the third modification, the base station 100 makesindication of different information for a case of Short PUCCH and for acase of Long PUCCH, with regard to the parameter (D) making up theinformation (X(0), X(1), . . . , X(N_(X))) regarding use of frequencydomain resources.

For example, the base station 100 makes indication of inter-clusterdistance using the parameter (D) for Short PUCCH, as illustrated in FIG.17A. On the other hand, the base station 100 makes indication offrequency hopping distance within the slot (or among slots) for LongPUCCH, as illustrated in FIG. 17B. That is to say, the parameter Dindicating the inter-cluster distance in the case of Short PUCCHindicates the frequency hopping distance in the case of Long PUCCH.

Thus, the overhead of parameters to be notified from the base station100 to the terminal 200 can be reduced by switching the value to beindicated using the parameter D in accordance with the PUCCH format.

Fourth Modification of First Embodiment

Information B regarding time domain resources (symbol position) will bedescribed.

NR supports Short PUCCH where PUCCH is transmitted using one symbol ortwo symbols, and Long PUCCH where PUCCH is transmitted using three ormore symbols, as described above.

In the fourth modification, the range of information (B(0), B(1), . . ., B(N_(B))) regarding time domain resources (symbol position) isdifferent between Short PUCCH and Long PUCCH. Further, the range ofinformation (B(0), B(1), . . . , B(N_(B))) regarding time domainresources (symbol position) may be different in accordance with thePUCCH transmission period (number of symbols in the PUCCH resources).

For example, the range of values that parameter B(n) can assume in aslot of seven symbols (#0 through #6) is 0 to 6 in a case of aone-symbol Short PUCCH. That is to say, PUCCH transmission can beperformed using any symbol within the slot in a case of a one-symbolShort PUCCH.

On the other hand, the range of values that parameter B(n) can assume is1 to 6 (starting position at end) or 0 to 5 (starting position fromstart) in a case of a two-symbol Short PUCCH. That is to say, anarrangement can be made where the one last or start symbol in the slotis not included in the range of values that B(n) can assume.

Making the minimum number of symbols to be four symbols in the case ofLong PUCCH is being studied. Accordingly, the range of values that B(n)can assume is 3 to 6 (starting position at end) or 0 to 3 (startingposition from start). That is to say, an arrangement can be made wherethe three last or start symbols in the slot are not included in therange of values that B(n) can assume.

Further, the information B(n) regarding time domain resources (symbolposition) may have the values that can be assumed limited in relationwith information regarding PUCCH transmission period (symbol) (C(0),C(1), . . . , C(N_(C))).

Inversely, there are cases where the information regarding PUCCHtransmission period (C(0), C(1), . . . , C(N_(C))) has the values thatit can assume restricted in relation with the information B(n) regardingtime domain resources (symbol position). That is to say, the range ofthe parameter B and the parameter C may be associated.

Thus, according to the fourth modification, overhead for higher layersignals can be reduced by reducing the number of bits necessary forindication of information B regarding time domain resources (symbolposition) or information C regarding PUCCH transmission period, or thenumber of candidates.

Fifth Modification of First Embodiment

In the following, a set of resources where PUCCH can be transmitted willbe defined as an uplink control resource set (Uplink control resourceset). FIG. 18 illustrates an example where two Uplink Control resourcesets Y1 and Y2 have been set.

In the fifth modification, the Semi-static resource configuration forPUCCH and the Uplink control resource set are associated, with theSemi-static resource configuration being different for each Uplinkcontrol resource set.

For example, different Uplink Control resource sets Y1 and Y2 are setfor Long PUCCH and Short PUCCH. Specifically, in the case of Long PUCCH,the Semi-static resource configuration for PUCCH is configured of theresource set Y1, and in a case of Short PUCCH, the Semi-static resourceconfiguration for PUCCH is configured of the resource set Y2.

Using group common downlink control signals (Group common PDCCH) withmultiple terminals as the object, in addition to terminal-specificPDCCH, is being studied in NR. In this case, indication can be made ofthe resource amounts (e.g., number of symbols) of the Uplink Controlresource set by Group common PDCCH. In this case, indication regardingthe resource amount of the Uplink Control resource set of Group commonPDCCH and the Semi-static resource configuration for PUCCH can beassociated. For example, an arrangement may be made where, in a casewhere there is indication of resource amount Z1 of the Uplink Controlresource set by Group common PDCCH, the Semi-static resourceconfiguration for PUCCH is configured of the resource set Y1, and in acase where there is indication of resource amount Z2 of the UplinkControl resource set by Group common PDCCH, the Semi-static resourceconfiguration for PUCCH is configured of the resource set Y2.

Also, elements that cause resource sets configuring the Semi-staticresource configuration to be different are not restricted to the abovedescribed Long PUCCH/Short PUCCH and indication of the resource amountof the Uplink Control resource set by Group common PDCCH, and may beSystem Frame Number (SFN), slot index, or uplink resource amount or thelike.

Also note that control resource set may be referred to as “CORESET”.

Notes on First Embodiment

A case has been described in the present embodiment where indication ismade of the Semi-static resource configuration for PUCCH usingterminal-specific higher layer signals. However, terminal-specific upperlayer signals cannot be used for indication regarding the Semi-staticresource configuration for PUCCH at the stage of initial access (e.g.,the stage before ST106 in FIG. 9). Accordingly, the Semi-static resourceconfiguration may be indicated using cell-specific or group-specifichigher layer signals such as SIB or the like, in the PUCCH resourceallocation at the initial access stage.

PUCCH resource allocation necessary at the initial access stage isallocation for PUCCH transmitting ACK/NACK signals as to Message 4.

The base station 100 can indicate the terminal 200 of the resourcesettings (Semi-static resource configuration) including the multiplecombination of parameters relating to PUCCH resources by cell-specificor group-specific higher layer signals such as SIB or the like (RMSI:Remaining minimum system information), and select one combination ofparameters relating to the PUCCH resources to be actually used,according to the number of bits of the DCI of the PDCCH where thecorresponding Message 4 has been allocated.

Note that the same Semi-static resource configuration is indicated amongthe multiple terminals 200 at this time, so an arrangement is necessaryto prevent PUCCH resources from colliding among terminals 200. Examplesof an arrangement necessary to prevent PUCCH resources from collidingamong terminals 200 include a method of correlating PUCCH resources withRNTI, PDCCH resource (e.g., CCE) or PDSCH resources.

Now, the smaller the overhead of cell-specific or group-specific higherlayer signals such as SIB or the like (RMSI) is, the better.Accordingly, several parameters (e.g., PUCCH transmission period) may bedecided beforehand regarding PUCCH resources allocation for transmissionof ACK/NACK signals to Message 4.

For example, with regard to the PUCCH transmission period (whether touse Long PUCCH or use Short PUCCH), Long PUCCH may be always used forACK/NACK signals to Message 4, since PUCCH transmission for ACK/NACKsignals to Message 4 needs robust transmission.

Also, the PUCCH transmission period for ACK/NACK signals to Message 4(whether to use Long PUCCH or use Short PUCCH) may be decided based onthe transmission method for Message 2 or Message 3. For example, in acase where Message 2 or Message 3 are slot-based transmission,Long-PUCCH may be used for ACK/NACK signals to Message 4, and in a casewhere Message 2 or Message 3 are non-slot-based transmission,Short-PUCCH may be used for ACK/NACK signals to Message 4.

Also, description has been made in the present embodiment regardingPUCCH resource allocation at the time of transmitting ACK/NACK signalsin downlink HARQ. However, the above-described PUCCH resource allocationis not restricted to a case of transmitting ACK/NACK signals in downlinkHARQ, and can be applied to a case of transmission of Aperiodic CSI.This same method can also be applied to resource allocation forAperiodic SRS that the terminal 200 transmits to the base station 100for uplink CSI measurement.

Second Embodiment

The base station and terminal according to the present embodiment havethe basic configuration in common with the base station 100 and terminal200 according to the first embodiment, so description will be made withreference to FIG. 7 and FIG. 8.

Description has been made in the first embodiment regarding PUCCHresource allocation in a case of transmitting ACK/NACK signals indownlink HARQ. Description has also been made in the first embodimentthat the same resource allocation method can be applied to a case oftransmitting Aperiodic CSI or Aperiodic SRS.

On the other hand, PUCCH is also used in a case of periodicallytransmitting CSI (periodic CSI) or SR or the like. In the same way,there is periodic transmission regarding SRS (periodic SRS) as well.

There is no dynamic indication to the terminal 200 by PDCCH with regardto these periodically-transmitted uplink control signals. Accordingly,the terminal 200 is not able to be indicated of Semi-static resourceconfiguration (multiple combinations of parameters) by higher layersignals and identify the combination of parameters relating theresources for actual transmission by DCI, as in the method illustratedin the first embodiment.

Accordingly, for resources in a case of transmitting periodic signals,there is a need for the base station 100 to make one or multipleindications to the terminal 200 beforehand regarding the combination ofparameters relating to resources that will actually be transmitted.

However, in a case where the slot type or the number of uplink symbolswithin the slot dynamically changes, as illustrated in FIG. 19 forexample, resources that have been Semi-statically indicated (set) are nolonger uplink resources, and it is conceivable that the terminal 200cannot use as uplink control signals. For example, in FIG. 19, theresources of PRB #0 and symbol #5 are Semi-statically set as uplinkresources. In this case, the terminal 200 was using these resources toperform periodic transmission of uplink control signals, but at acertain timing, the resources of PRB #0 and symbol #5 have been set tobe a gap, and the resources allocated to Semi-static are no longerusable as resources.

Now, the base station 100 can indicate the terminal 200 of slot types orresource amount (number of symbols, etc.) usable for uplink by Groupcommon PDCCH.

Accordingly, in the present embodiment, the terminal 200 receives anddecodes the Group common PDCCH and obtain information relating toresources usable for uplink, and thereby judges whether or not resourcesthat had been allocated to Semi-static can be used as resources fortransmitting periodic signals. In a case where resources that had beenallocated to Semi-static can be used as resources for transmittingperiodic signals, the terminal 200 uses these resources to transmitperiodic uplink control signals (CSI, SRS, SR).

On the other hand, in a case where resources that had been allocated toSemi-static cannot be used as resources for transmitting periodicsignals, the terminal 200 may implement the following methods 1 and 2.

<Method 1>

The terminal 200 drops transmission of periodic signals(non-transmission). Now, it is conceivable that even if part oftransmission of periodic signals is missing, there are no great effectson characteristics. Accordingly, by the terminal 200 not transmittingperiodic signals by symbols that are not uplink resources, interferencewith signals transmitted by other terminals using these resources can beprevented.

<Method 2>

The terminal 200 identifies resources for transmitting periodic signals,using information relating to resources useable for uplink that isobtained from Group common PDCCH. For example, in a case where thenumber of uplink symbols N_(UL) is indicated by Group common PDCCH, theterminal 200 identifies the symbol position B(n) by B(n) mod N_(UL).According to this method, there is no need to drop periodic signals.

As one example, assumption will be made that three symbols from the endof the slot have been indicated as symbol position B(n). At this time,when the last two symbols in the slot are indicated by Group commonPDCCH as number of symbols N_(UL), symbol position B(n) is no longer anuplink resource. In this case, the terminal 200 identifies one symbolfrom the end of the slot as symbol position B(n) due to B(n) mod N_(UL).Accordingly, even in a case where the number of uplink symbols withinthe slot has been dynamically changed, the terminal 200 can transmituplink control signals using uplink resources after the change.

As described above, according to the present embodiment, PUCCH resourcescan be flexibly allocated to uplink control signals periodicallytransmitted, such as CSI (periodic CSI), SR, or the like.

Third Embodiment

The base station and terminal according to the present embodiment havethe basic configuration in common with the base station 100 and terminal200 according to the first embodiment, so description will be made withreference to FIG. 7 and FIG. 8.

Description was made in the second embodiment regarding uplink resourcesallocated to periodically transmitted signals, of a case whereSemi-statically indicated resources are no longer uplink resources dueto the slot type or the number of uplink symbols within the slotdynamically changing, and cannot be used for transmission of thesesignals (e.g., see FIG. 19).

On the other hand, regarding resources transmitting non-periodic signals(ACK/NACK signals, Aperiodic CSI, Aperiodic SRS, etc.) described in thefirst embodiment as well, there is the possibility that the entirety ofa Semi-statically indicated Resource configuration is no longer uplinkresources due to the slot type or number of uplink symbols within theslot dynamically changing, and cannot be used for transmission of thesesignals.

In such a case as well, it is undesirable for the terminal 200 to dropnon-periodic signals (particularly ACK/NACK and so forth) as in Method 1of the second embodiment. In the present embodiment, the base station100 and terminal 200 implement the following method.

Specifically, first, the base station 100 instructs the terminal 200 toreceive and decode the Group common PDCCH using a terminal-specificPDCCH or the like. Note however, in a case where the terminal 200constantly receives and decodes the Group common PDCCH, this instructionby the base station 100 is unnecessary.

Next, the terminal 200 receives and demodulates the Group common PDCCH,and obtains information relating to resources usable for uplink. Theterminal 200 then identifies resources transmitting periodic signals,using information relating to resource usable for uplink, that has beenobtained from the Group common PDCCH. For example, in a case where thenumber of uplink symbols N_(UL) has been indicated by the Group commonPDCCH, the terminal 200 identifies the symbol position B(n) from B(n)mod N_(UL).

Accordingly, even in a case where resources transmitting non-periodicsignals cannot be used due to the slot type or number of uplink symbolswithin the slot dynamically changing, the terminal 200 can identifyresources usable for transmission of these signals, and performtransmission, without dropping non-periodic signals.

Fourth Embodiment

The base station and terminal according to the present embodiment havethe basic configuration in common with the base station 100 and terminal200 according to the first embodiment, so description will be made withreference to FIG. 7 and FIG. 8.

In the first embodiment, description has been made regarding a methodwhere, with regard to allocation of PUCCH resources for transmission ofuplink control signals (e.g., ACK/NACK signals), resource settings(Semi-static resource configuration) including multiple combinations ofparameters relating to PUCCH resources are indicated to the terminal bythe base station using higher layer signals, and one combination ofparameters relating to the PUCCH resources to be actually used isselected by several bits of DCI of the PDCCH where correspondingdownlink data has been allocated. Description has also been made in thefirst embodiment that parameters relating to PUCCH resources may includetime domain resources (slot) and time domain resources (symbolposition).

Now, NR supports transmission in units of slots (also referred to asSlot-based transmission or PDSCH mapping type A) and transmission innon-slot units (also referred to as Non-slot-based transmission,mini-slot-based transmission, or PDSCH mapping type B).

FIG. 20A and FIG. 20B illustrate an example of slot-based transmission.In FIG. 20A, the downlink data channel (PDSCH) mapped to the symbols #2through #13 of slot n is scheduled by the downlink control channel(PDCCH) mapped to the symbols #0 and #1 of slot n. Also, the ACK/NACKsignals corresponding to the PDSCH illustrated in FIG. 20A aretransmitted using the PUCCH of slot n+k illustrated in FIG. 20B. Here, kis an integer of 0 or greater.

FIG. 21 illustrates an example of non-slot-based transmission. In FIG.21, PDSCH mapped to symbols #6 and #7 of slot n are scheduled by PDCCHmapped to symbols #4 and #5 of slot n. Also, in FIG. 21, ACK/NACKsignals corresponding to PDSCH are transmitted using PUCCH of symbols#12 and #13 in slot n.

Note that a set of resources capable of transmitting PDCCH is definedhere as a downlink control resource set (Downlink control resource set,DL CORESET).

In slot-based transmission, DL CORESET is always mapped to the first twoor three symbols of the slot, as illustrated in FIG. 20A. On the otherhand, in non-slot-based transmission, DL CORESET can be mapped to anysymbol in the slot, as illustrated in FIG. 21. For example, the DLCORESET can be mapped to the first two or three symbols of the slot evenin non-slot-based transmission.

In a case where DL CORESET has been mapped to the first two or threesymbols of the slot, the terminal has to distinguish whether the DLCORESET is a DL CORESET from slot-based transmission, or a DL CORESETfrom non-slot-based transmission. Accordingly, in a case where DLCORESET has been mapped to the first two or three symbols of the slot,it is assumed that indication will be used to distinguish whether the DLCORESET is a DL CORESET from slot-based transmission, or a DL CORESETfrom non-slot-based transmission. On the other hand, in a case where DLCORESET has been mapped to other than the first two or three symbols ofthe slot, the terminal can recognize that the DL CORESET is a DL CORESETfrom non-slot-based transmission.

Now, in slot-based transmission, indication of the slot position of timedomain resources that is a parameter relating to PUCCH resources, isimportant, and it is necessary to be able to allocate slot positionsmore flexibly. On the other hand, in non-slot-based transmission, beingable to allocate symbol positions more flexibly is necessary rather thanslot positions, with regard to time domain resources that is a parameterrelating to PUCCH resources.

Accordingly, in the present embodiment, the indication method isdifferent for time domain resources (slot) and time domain resources(symbol position) serving as a parameter relating to PUCCH resourcesregarding the slot-based transmission and the non-slot-basedtransmission.

Specifically, in slot-based transmission, no parameter relating to timedomain resources (slot) is included in the resource settings(Semi-static resource configuration) indicating the combination ofmultiple parameters relating to PUCCH resources. The base station 100indicates the terminal 200 of resource settings (Semi-static resourceconfiguration) including the combination of multiple parameters relatingto PUCCH resources, using higher layer signals. The base station 100also selects one combination of parameters relating to PUCCH resourcesto be actually used, by several bits of DCI of PDCCH to whichcorresponding downlink data has been allocated. At this time, timedomain resources (symbol position) are included in the resource settingsindicating the combination of multiple parameters relating to PUCCHresources. On the other hand, the base station 100 indicates theterminal 200 of parameters (settings) relating to time domain resources(slot) independently from the above resource settings using higher layersignals. The base station 100 then selects one slot (slot position) tobe actually used, by several bits of DCI of PDCCH to which correspondingdownlink data has been allocated.

On the other hand, in non-slot-based transmission, information relatingto both time domain resources (slot) and time domain resources (symbolposition) are included in resource settings (Semi-static resourceconfiguration) indicating multiple combinations of parameters regardingPUCCH resources. At this time, it is conceivable that informationrelating to slots is not necessary as information relating to timedomain resources in non-slot-based transmission. Accordingly, the basestation 100 is capable of indication of information relating to timedomain resources in units of symbols, in the above-described resourcesettings.

Also, in a case where DL CORESET is mapped to the first two or threesymbols of the slot, the DCI size in slot-based transmission and the DCIsize in non-slot-based transmission may be made to be the same in theindication of parameters (including information relating to slot)regarding PUCCH resources to be actually used, in order to reduce thenumber of times of performing blind decoding regarding PDCCH.

Accordingly, at least in a case where DL CORESET is mapped to the firsttwo or three symbols of the slot, the base station 100 in the presentembodiment may select and indicate of parameters relating to PUCCHresources using DCI of (X+Y) bits as illustrated in FIG. 22, to make theDCI size in slot-based transmission and the DCI size in non-slot-basedtransmission to be the same.

In slot-based transmission (PDSCH mapping type A), X bits are used forselection of time domain resources (slot) indicated to the terminal 200independently from other parameters regarding PUCCH resources, and Ybits are used for selecting one combination of parameters regardingPUCCH resources, as illustrated in FIG. 22. On the other hand, innon-slot-based transmission (PDSCH mapping type B), X+Y bits are usedfor selection of one combination of parameters relating to PUCCHresources.

Accordingly, the base station 100 can allocate slot position moreflexibly by indicating the terminal 200 of slot positions independentlyfrom parameters relating to other PUCCH resources in slot-basedtransmission. Also, in non-slot-based transmission, the base station 100can allocate symbol positions more flexibly by indication of PUCCHresources in symbol granularity, for example. Thus, according to thepresent embodiment, flexible allocation of time domain resources (slotor symbol position) that is appropriate for each of slot-basedtransmission and non-slot-based transmission with regard to allocationof PUCCH resources can be performed.

Also, the DCI size is the same for slot-based transmission andnon-slot-based transmission, so even in a case where DL CORESET ismapped to the first two or three symbols of the slot, there is no needto increase the number of times of blind decoding of PDCCH at theterminal 200.

Modification of Fourth Embodiment

A case has been described in the fourth embodiment where the basestation 100 selects/indicates parameters regarding PUCCH resources usingDCI of X+Y bits to make the DCI size the same for slot-basedtransmission and non-slot-based transmission, in a case where DL CORESETis mapped to the first two or three symbols of the slot.

On the other hand, in a case where DL CORESET has been mapped to otherthan the first two or three symbols of the slot, the terminal 200 canrecognize that this DL CORESET is a DL CORESET from non-slot-basedtransmission. Further, non-slot-based transmission is expected to useURLLC (Ultra Reliable Low Latency Communication) where high reliabilityis required, so the DCI size is preferably minimized.

Accordingly, as a modification of the fourth embodiment, in a case whereDL CORESET has been mapped to other than the first two or three symbolsof the slot, the base station 100 may select and indicate of parametersregarding PUCCH resources using DCI of Y bits for DL CORESET innon-slot-based transmission, as illustrated in FIG. 23.

Thus, the DCI size can be reduced, encoding efficiency improved, and thetransmission quality/reliability of PDCCH improved.

Fifth Embodiment

The base station and terminal according to the present embodiment havethe basic configuration in common with the base station 100 and terminal200 according to the first embodiment, so description will be made withreference to FIG. 7 and FIG. 8.

As described earlier, the number of symbols in a slot that can be usedas PUCCH resources are dependent on the type of slot (Downlink centricslot, Uplink centric slot, Downlink only slot, Uplink only slot, and soforth) as illustrated in FIG. 3 in NR. The terminal can know the type ofslot (downlink symbol count, uplink symbol count, etc.) from one of thefollowing indications.

The first is Semi-static configuration (alternately referred to asSemi-static DL/UL configuration). Semi-static configuration is indicatedby RRC signals. The second is SFI (Slot Format Indicator). SFI isindicated by group common downlink control signals (Group common PDCCH).The third is UE-specific assignment. UE-specific assignment is indicatedby terminal-specific DCI. Information relating to the PUCCH transmissionperiod in the resource settings indicating multiple parametercombination regarding PUCCH resources in the first embodiment also is aUE-specific assignment.

For example, in a case where the terminal can use a Semi-staticconfiguration or SFI, the terminal can Implicitly decide the PUCCHtransmission period and symbol position from the Semi-staticconfiguration or SFI. That is to say, in a case where the terminal canuse a Semi-static configuration or SFI, information relating to thePUCCH transmission period (symbol count) set by RRC signals does nothave to be restricted to specific numerical values (e.g., C symbols (C=1through 14), etc.).

Accordingly, in the present embodiment, a method where, in the resourcesettings (Semi-static resource configuration) by higher layer signals,the terminal 200 is not indicated of specific numerical values regardingthe PUCCH transmission period and symbol positions by the base station100, and the terminal 200 implicitly decides the PUCCH transmissionperiod and symbol positions from the Semi-static configuration or SFI.

The base station 100 indicates the terminal 200 of the resource settings(Semi-static resource configuration) including multiple parametercombination regarding PUCCH resources by higher layer signals, andselects one combination of parameters regarding PUCCH resources to beactually used, by several bits of DCI of PDCCH to which correspondingdownlink data has been allocated. In the present embodiment, the basestation 100 makes indication regarding one or both of parametersregarding time domain resources (symbol) and parameters regarding PUCCHtransmission period (the number of symbols) in the resource settings(Semi-static resource configuration) including multiple parametercombination regarding PUCCH resources, not by specific numerical values,but by a command such as, for example, “follow Semi-staticconfiguration”, “follow SFI”, or the like.

In a case where one or both of parameters regarding time domainresources (symbol) and parameters regarding PUCCH transmission periodfor parameter combinations regarding PUCCH resources indicated by DCIindicate “follow Semi-static configuration” or “follow SFI”, theterminal 200 transmits PUCCH using uplink symbols obtained by theSemi-static configuration indicated by RRC symbols or uplink symbolsindicated by SFI.

That is to say, in the present embodiment, the resource settings(Semi-static resource configuration) indicated by higher layer signalsdo not include specific numerical values indicating symbol position inthe slot or number of symbols, and the terminal 200 obtains the valueindicting the symbol position or number of symbols of the PUCCHresources from the Semi-static configuration or SFI that are informationindicating the slot type.

Note that the command relating to the PUCCH transmission period is notrestricted to the commands indicating “follow Semi-static configuration”or “follow SFI”, and may be a command indicating such as “all UL symbolsin slot”, “all UL symbols in slot−X symbols”, or the like. Note that Xsymbols here may be a cell-specific semi-static value or may be a valuenotified by SFI or UE-specific assignment. X may be in a range of 1 to 6symbols.

FIG. 24A illustrates a setting example of PUCCH resources according tothe fifth embodiment, and FIG. 24B illustrates an example of thecorrelation between DCI bits and Semi-static resource configurationaccording to the fifth embodiment.

With regard to the parameter B regarding time domain resources (symbol)and parameter C regarding PUCCH transmission period, indication is madeof a command “all UL symbols in slot” for implicitly deciding in FIG.24B. Note that PUCCH resources settings are not restricted to theexample illustrated in FIG. 24B, and, for example, may includecombinations where specific numerical values are set for parameter Bregarding time domain resources (symbol) and parameter C regarding PUCCHtransmission period.

In the case of FIG. 24B, time domain resources (symbol) can beimplicitly decided by the terminal 200 to be the first UL symbol in theslot obtained from the Semi-static configuration or SFI. For example,the terminal 200 is indicated by Semi-static configuration or SFI inFIG. 24A that the PUCCH resources are at symbols #8 through #13 in slotn. Accordingly, the terminal 200 decides the symbol #8 that is the firstUL symbol within the slot n to be the allocated time domain resources(symbol).

Also, in the case in FIG. 24B, the terminal 200 decides the PUCCHtransmission period from UL symbols within the slot obtained from theSemi-static configuration or SFI. For example, in FIG. 24A, the terminal200 decides the six symbols of symbol #8 through #13 that are PUCCHresources within the slot n to be the allocated PUCCH transmissionperiod (number of symbols).

Accordingly, the need for explicit indication of resources is done awaywith regarding part of the parameters of PUCCH resources (time domainresources (symbol) and PUCCH transmission period), so the overhead ofDCI bits for PUCCH resources indication can be reduced. Alternatively,in a case where the DCI bits for PUCCH resources indication are the same(a case of a fixed value), there is no more need to take the time domainresources (symbol) and PUCCH transmission period into consideration withregard to parameter combinations, so the allocation of number of DCIbits increases for other parameters, and accordingly the otherparameters can be indicated of more flexibly.

Also, in a case of not using implicit indication as in the presentembodiment, the time domain resources of PUCCH are decided byUE-specific assignment. In a case where the terminal 200 has beenindicated of both the Semi-static configuration or SFI, and UE-specificassignment, the base station 100 cannot control the degree of priorityof the respective indications, and UE-specific assignment is alwaysgiven priority. Conversely, according to the present embodiment, in acase where the terminal 200 has been indicated of both the Semi-staticconfiguration or SFI, and UE-specific assignment, the base station 100can control the degree of priority of multiple indications indicatingslot type (Semi-static configuration/SFI and UE-specific assignment).For example, in a case of including specific numerical values (i.e.,indication by UE-specific assignment) as parameters relating to timedomain resources (symbol) or PUCCH transmission period (number ofsymbols) in DCI indicating a combination of parameters relating to PUCCHresources to be actually used, in the resource settings (Semi-staticresource configuration) including multiple parameter combinationsregarding PUCCH resources, the base station 100 can raise the degree ofpriority of UE-specific assignment. On the other hand, in a case ofincluding the above-described commands to reference Semi-staticconfiguration/SFI as parameters relating to time domain resources(symbol) or PUCCH transmission period (number of symbols) in DCIindicating a combination of parameters relating to PUCCH resources to beactually used, in the resource settings (Semi-static resourceconfiguration) including multiple parameter combinations regarding

PUCCH resources (i.e., Implicit notification), the base station 100 canraise the degree of priority of Semi-static configuration/SFIindication.

Modification of Fifth Embodiment

Description has been made in the fifth embodiment regarding a case wherePUCCH is transmitted by single slot (e.g., see FIG. 24A). However, PUCCHcan be transmitted using multiple slots in NR. In a case of transmittingPUCCH using multiple slots, there are cases where the slot types (numberof UL symbols within slots) differ among the multiple slots transmittingPUCCH.

Accordingly, a case of transmitting PUCCH using multiple slots will bedescribed in a modification of the fifth embodiment.

Specifically, in a case where Semi-static configuration or SFI can beused, the terminal 200 transmits PUCCH using uplink symbols indicated bythe uplink symbol obtained from Semi-static configuration or SFI for thetime domain resources (symbol) and PUCCH transmission period, in thesame way as in the fifth embodiment.

On the other hand, in a case where Semi-static configuration or SFIcannot be used, the terminal 200 transmits PUCCH using uplink symbolsindicated by UE-specific assignment (e.g., the time domain resources(symbol) and PUCCH transmission period decided by the combination ofparameters regarding PUCCH resources).

A case is also conceivable where the number of uplink symbols obtainedby Semi-static configuration or uplink symbols indicated by SFI issmaller than four symbols. It is conceivable in NR that only Long PUCCHis capable of PUCCH transmission using multiple slots. Accordingly, in acase where the number of uplink symbols obtained by Semi-staticconfiguration or UL symbols indicated by SFI is smaller than foursymbols, the terminal 200 may drop or postpone transmission of PUCCH.

FIG. 25A through FIG. 25D illustrates setting examples of PUCCHresources in slot n through slot n+3 according to a modification of thefifth embodiment. That is to say, FIG. 25A through FIG. 25D illustrate acase of the terminal 200 transmitting PUCCH using four slots.

The terminal 200 decides PUCCH resources allocated to the terminal 200for each slot, based on UL symbols (symbol position and number ofsymbols) indicated by Semi-static configuration or SFI regarding eachslot as in FIG. 24A, as illustrated in FIG. 25A through FIG. 25D.Accordingly, even if the slot type (number of UL symbols within theslot) differs among the multiple slots transmitting PUCCH as illustratedin FIG. 25A through FIG. 25D, the terminal 200 can identify the PUCCHresources allocated to each slot.

In a case of allocating PUCCH resources for each slot in PUCCHtransmission using multiple slots, overhead of resource allocationincreases. Conversely, according to the modification of the fifthembodiment, the terminal 200 can decide PUCCH resources for each slot bySemi-static configuration or SFI, so overhead for resource allocationcan be reduced. Also, even in a case of transmitting PUCCH using slotswith different number of UL symbols in the slots, the terminal 200 canuse the UL symbols without waste, so resource usage efficiency can beimproved.

Sixth Embodiment

The base station and terminal according to the present embodiment havethe basic configuration in common with the base station 100 and terminal200 according to the first embodiment, so description will be made withreference to FIG. 7 and FIG. 8.

In the first embodiment, description has been made, with regard toallocation of PUCCH resources for transmitting uplink control signals(e.g., ACK/NACK signals), regarding a method where the base stationindicates the terminal of resource settings (Semi-static resourceconfiguration) including multiple parameter combinations regarding PUCCHresources by higher layer signals, and one combination of parametersregarding PUCCH resources to be actually used is selected by severalbits of the DCI of the PDCCH to which the corresponding downlink datahas been allocated. Description has also been made in the firstembodiment that parameters regarding PUCCH resources can include timedomain resources (slot) and time domain resources (symbol position).

On the other hand, overhead of DCI bits for PUCCH resources indicationcan be reduced by doing away with explicit indication of resources forpart of the parameters of PUCCH resources, as described in the fifthembodiment. Alternatively, in a case where the DCI bits are the same (acase of a fixed value), there is no need to take part of the parametersinto consideration, so the other parameters can be indicated of moreflexibly.

In the present embodiment, a method of adding a function of implicitindication is described regarding part of the parameters of PUCCHresources.

The base station 100 indicates the terminal 200 of resource settings(Semi-static resource configuration) including multiple parametercombinations regarding PUCCH resources by higher layer signals, andselects one combination of parameters regarding PUCCH resources to beactually used by several bits of the DCI of the PDCCH to which thecorresponding downlink data has been allocated. The present embodimenthas, at this time, a function of implicit indication regarding one ormultiple parameters of the resource settings (Semi-static resourceconfiguration) including multiple parameter combinations regarding PUCCHresources.

For example, information relating to frequency resources or informationrelating to code resources (cyclic shift or time domain orthogonal code(Orthogonal Cover Code (OCC)) are conceivable of parameters regardingwhich an implicit indication function is added. Note that parametersregarding which an implicit indication function is added are notrestricted to these.

As for a function of implicit notification, there is a method of addingadditional offset to a parameter indicated by DCI. Examples ofadditional offset that can be used include C-RNTI mod X, CCE mod X, andso forth, based on the identifier (C-RNTI: Cell-Radio Network TemporaryIdentifier) of the terminal 200 or CCE (Control Channel Element) usedregarding the terminal 200. Also, PDSCH resources may be used instead ofCCE. The value of X may be a fixed value, or a value set by RRC signals.

FIG. 26 illustrates an example of PUCCH resources settings in thepresent embodiment. Allocation of PUCCH resources #0 through #7 will bedescribed in FIG. 26. For example, in a case of Explicit indicationalone (Explicit indication), there is a need to make indication of eightPUCCH resources #0 through #7 by 3-bit DCI.

As opposite to this, in the present embodiment (Explicit +Implicit), thebase station 100 makes indication of eight PUCCH by one bit, forexample, and can avoid collision of PUCCH resources among terminals 200by Implicit notification (e.g., additional offset).

For example, the base station 100 groups the eight PUCCH resources #0through #7 (candidate values) into PUCCH resources #0 through #3 andPUCCH resources #4 through #7 in FIG. 26, and explicitly indicates theterminal of any one (nod) of the multiple (two) groups using 1-bit DCI.The terminal 200 then adds additional offset (CCE mod 4) to the n_(DCI)indicated by the 1-bit DCI, and implicitly decides PUCCH resources.Accordingly, the base station 100 can allocate PUCCH resources for eachof the PUCCH resources #0 through #7 while avoiding collision of PUCCHresources among the terminals 200.

Thus, according to the present embodiment, the terminal 200 is indicatedof at least one parameter of multiple parameters regarding PUCCHresources by DCI (Explicit notification) indicating any one of multiplegroups where multiple candidate values of the parameter have beengrouped, and offset (Implicit notification) set to each terminal 200.

Accordingly, there is no more need, or less need, for explicitindication of resources by DCI regarding part of the parameters of PUCCHresources, so the overhead of DCI bits for PUCCH resource indication canbe reduced. Alternatively, in a case where the number of DCI bits is thesame (a case of a fixed value), there is no need to take part of theparameters into consideration regarding parameter combinations, or thenumber of bits for indication is reduced, so allocation of number of DCIbits increases for other parameters, and the other parameters can beindicated of more flexibly.

Embodiments of the present disclosure have been described above.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. The functional blocks such asused in the above-described embodiments typically are partly or fullyrealized as LSI that is an integrated circuit, and the processesdescribed in the above embodiments may be partially or entirelycontrolled by one LSI or a combination of LSIs. These LSIs may beindividually formed into one chip, or part or all of the functionalblocks may be included in one chip. LSIs may have data input and output.There are different names of LSIs such as IC, system LSI, super LSI, andultra LSI, depending on the degree of integration. The circuitintegration technique is not restricted to LSIs, and dedicated circuits,general-purpose processors, or dedicated processors may be used torealize the same. An FPGA (Field Programmable Gate Array) which can beprogrammed after manufacturing the LSI, or a reconfigurable processorwhere circuit cell connections and settings within the LSI can bereconfigured, may be used. The present disclosure may be realized bydigital processing or analog processing. Further, in the event of theadvent of an integrated circuit technology which would replace LSIs byadvance of semiconductor technology or a separate technology derivedtherefrom, such a technology may be used for integration of thefunctional blocks, as a matter of course. Application of biotechnologyand so forth is a possibility.

A base station according to the present disclosure includes: a circuitthat selects, from a plurality of combinations of parameters regardinguplink control channel (PUCCH) resources, one combination; and atransmitter that indicates a terminal of resource settings including theplurality of combinations by higher layer signaling, and indicates theterminal of the one combination that has been selected by dynamicsignaling.

In the base station according to the present disclosure, the pluralityof parameters include a parameter indicating frequency domain resources,a parameter indicating a slot, a parameter indicating a symbol positionwithin the slot, and a parameter indicating the number of symbol.

In the base station according to the present disclosure, the frequencydomain resources are represented by an offset value indicating a startposition from an edge of a band, the number of consecutive resourceblocks, the number of clusters, and an inter-cluster distance.

In the base station according to the present disclosure, the offsetvalue indicates a start position from an edge of the band that thetermination supports within a system band, and a range of the offsetvalue is a range of bandwidth of the band that the termination supportswithin the system band.

In the base station according to the present disclosure, the range ofthe offset value is a range of half the band.

In the base station according to the present disclosure, in a case wherethe number of symbols of the PUCCH resources is a threshold value orgreater, the source block count is 1.

In the base station according to the present disclosure, the number ofconsecutive resource blocks is associated with the PUCCH format.

In the base station according to the present disclosure, in a case wherethe number of symbols of the PUCCH resources is a threshold value orgreater, the cluster count is 1.

In the base station according to the present disclosure, theinter-cluster distance is identified from the bandwidth of the band andthe number of consecutive resource blocks.

In the base station according to the present disclosure, the number ofconsecutive resource blocks and the inter-cluster distance are powers of2.

In the base station according to the present disclosure, in a case wherea plurality of different subcarrier spacings are set in a same band, thenumber of consecutive resource blocks and the inter-cluster distance ina first subcarrier spacing are each identified from the number ofconsecutive resource blocks and the inter-cluster distance in a secondsubcarrier spacing.

In the base station according to the present disclosure, the parameterthat indicates the inter-cluster distance in a case where the number ofsymbols of the PUCCH resources is smaller than a threshold value,indicates a frequency hopping distance in a case where the number ofsymbols of the PUCCH resources is the threshold value or greater.

In the base station according to the present disclosure, a range of theparameter indicating the symbol position within the slot differs betweena case where the number of symbols of the PUCCH resources is smallerthan a threshold value, and in a case where the number of symbols of thePUCCH resources is the threshold value or greater.

In the base station according to the present disclosure, a range of theparameter indicating the symbol position within the slot, and theparameter indicating the number of symbols of the PUCCH resources, areassociated.

In the base station according to the present disclosure, a plurality ofuplink control resource sets are associated with the resource settingsthat are different from each other.

In the base station according to the present disclosure, the pluralityof parameters included in the resource settings are configured based onone control resource set associated with the PUCCH format, out of theplurality of control resource sets.

In the base station according to the present disclosure, a resourceamount of the control resource set is indicated to the terminal from thebase station by Group common PDCCH, and the different resource settingsare each associated with the resource amount indicated by the Groupcommon PDCCH.

In the base station according to the present disclosure, one of a firsttransmission method that is in slot based, and a second transmissionmethod that is in non-slot based, is set. In a case where the firsttransmission method is set, at least a parameter indicating a symbolposition is included in the plurality of parameters, and the transmitterindicates the terminal of a parameter indicating a slot, independentlyfrom the resource settings. In a case where the second transmissionmethod is set, at least the parameter indicating the slot and aparameter indicating a symbol position within the slot, are included inthe plurality of parameters.

In the base station according to the present disclosure, a numericalvalue indicating a symbol position within a slot or the number ofsymbols is not included in the resource settings, and a numerical valueindicating the symbol position or the number of symbols is indicated tothe terminal by information indicating a type of the slot.

In the base station according to the present disclosure, the terminal isindicated of at least one parameter of the plurality of parameters bythe dynamic signaling indicating one of a plurality of groups where aplurality of candidate values of the parameter have been grouped, andoffset set for each terminal.

A terminal according to the present disclosure includes: a receiver thatreceives higher layer signaling including resource settings indicating aplurality of combinations of parameters regarding uplink control channel(PUCCH) resources, and receives dynamic signaling indicating onecombination out of the plurality of combinations; and a transmitter thattransmits uplink control signals by the PUCCH resources represented bythe plurality of parameters corresponding to the one combinationindicated by the dynamic signaling, out of the plurality ofcombinations.

A communication method according to the present disclosure includes:selecting, from a plurality of combinations of parameters regardinguplink control channel (PUCCH) resources, one combination; andindicating a terminal of resource settings including the plurality ofcombinations by higher layer signaling, and indicating the terminal ofthe one combination that has been selected by dynamic signaling.

A communication method according to the present disclosure includes:receiving higher layer signaling including resource settings including aplurality of combinations of parameters regarding uplink control channel(PUCCH) resources, and receiving dynamic signaling indicating onecombination out of the plurality of combinations; and transmittinguplink control signals by the PUCCH resources represented by theplurality of parameters corresponding to the one combination indicatedby the dynamic signaling, out of the plurality of combinations.

An embodiment of the present disclosure is useful in a mobilecommunication system.

REFERENCE SIGNS LIST

-   100 base station-   101, 209 control unit-   102 data generating unit-   103, 107, 110, 211, 214 encoding unit-   104 retransmission control unit-   105, 108, 111, 212, 215 modulating unit-   106 higher layer control signal generating unit-   109 downlink control signal generating unit-   112, 217 signal allocation unit-   113, 218 IFFT unit-   114, 219 transmission unit-   115, 201 antenna-   116, 202 reception unit-   117, 203 FFT unit-   118, 204 extracting unit-   119 CSI demodulating unit-   120 SRS measuring unit-   121 modulating/demodulating unit-   122 determining unit-   200 terminal-   205 downlink control signal demodulating unit-   206 higher layer control signal demodulating unit-   207 downlink data signal demodulating unit-   208 error detecting unit-   210 CSI generating unit-   213 ACK/NACK generating unit-   216 SRS generating unit

1. A terminal comprising: a receiver, which, in operation, receivesinformation indicating a set of parameters related to a physical uplinkcontrol channel (PUCCH) resource; and a transmitter, which, inoperation, transmits uplink control information using the PUCCH resourcedetermined based on the information, wherein the set of parameters for agiven PUCCH format does not include a number of resource block(s) forPUCCH transmission, and the number of resource block(s) for the givenPUCCH format is fixed.
 2. The terminal according to claim 1, wherein theset of parameters includes a starting resource block.
 3. The terminalaccording to claim 2, wherein the starting resource block is representedas an offset from an edge of a bandwidth.
 4. The terminal according toclaim 3, wherein the offset is in a range of a bandwidth that theterminal supports in a system bandwidth.
 5. The terminal according toclaim 1, wherein a plurality of sets, each set including parametersrelated to the PUCCH resource, are configured to the terminal, and theinformation indicates one set of the plurality of sets.
 6. The terminalaccording to claim 5, wherein the plurality of sets are semi-staticallyconfigured by a higher layer, and the information is received in adownlink control information.
 7. The terminal according to claim 5,wherein the information is dedicated to the terminal.
 8. The terminalaccording to claim 1, wherein the receiver, in operation, receives adownlink control information, and the transmitter, in operation,transmits the uplink control information using the PUCCH resource thatis based on the information and that is associated with a resource usedfor transmission of the downlink control information.
 9. The terminalaccording to claim 8, wherein the information is specific to a cell or agroup of terminals.
 10. The terminal according to claim 1, wherein thereceiver, in operation, receives a downlink control information relatedto a symbol available for uplink, and the transmitter, in operation,transmits the uplink control information using the symbol available foruplink in the PUCCH resource determined based on the information. 11.The terminal according to claim 10, wherein when the PUCCH resourcedetermined based on the information is not the symbol available foruplink, the uplink control information is not transmitted.
 12. Theterminal according to claim 10, wherein the uplink control informationis a periodically transmitted signal.
 13. A communication methodcomprising: receiving information indicating a set of parameters relatedto a physical uplink control channel (PUCCH) resource; and transmittinguplink control information using the PUCCH resource determined based onthe information, wherein the set of parameters for a given PUCCH formatdoes not include a number of resource block(s) for PUCCH transmission,and the number of resource block(s) for the given PUCCH format is fixed.